Class MatchException

java.lang.MatchException

All Implemented Interfaces:: Serializable

public final class MatchException extends RuntimeException

Thrown to indicate an unexpected failure in pattern matching.

MatchException may be thrown when an exhaustive pattern matching language construct (such as a switch expression) encounters a value that does not match any of the specified patterns at run time, even though the construct has been deemed exhaustive. This is intentional and can arise from a number of cases:

Separate compilation anomalies, where parts of the type hierarchy that the patterns reference have been changed, but the pattern matching construct has not been recompiled. For example, if a sealed interface has a different set of permitted subtypes at run time than it had at compile time, or if an enum class has a different set of enum constants at runtime than it had at compile time, or if the type hierarchy has been changed in some incompatible way between compile time and run time.
null values and nested patterns involving sealed classes. If, for example, an interface I is sealed with two permitted subclasses A and B, and a record class R has a single component of type I, then the two record patterns R(A a) and R(B b) together are considered to be exhaustive for the type R, but neither of these patterns will match against the result of new R(null).
null values and nested record patterns. Given a record class S with a single component of type T, where T is another record class with a single component of type String, then the nested record pattern R(S(var s)) is considered exhaustive for the type R but it does not match against the result of new R(null) (whereas it does match against the result of new R(new S(null)) does).

MatchException may also be thrown by the process of pattern matching a value against a pattern. For example, pattern matching involving a record pattern may require accessor methods to be implicitly invoked in order to extract the component values. If any of these accessor methods throws an exception, pattern matching completes abruptly and throws MatchException. The original exception will be set as a cause of the MatchException. No suppressed exceptions will be recorded.

See Java Language Specification:

14.11.3 Execution of a switch Statement
14.30.2 Pattern Matching
15.28.2 Run-Time Evaluation of switch Expressions

Since:

See Also:

Constructor Summary

Constructor	Description
`MatchException(String message, Throwable cause)`	Constructs an `MatchException` with the specified detail message and cause.

Method Summary

Methods declared in class Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Modifier and Type	Method	Description
`final void`	`addSuppressed(Throwable exception)`	Appends the specified exception to the exceptions that were suppressed in order to deliver this exception.
`Throwable`	`fillInStackTrace()`	Fills in the execution stack trace.
`Throwable`	`getCause()`	Returns the cause of this throwable or `null` if the cause is nonexistent or unknown.
`String`	`getLocalizedMessage()`	Creates a localized description of this throwable.
`String`	`getMessage()`	Returns the detail message string of this throwable.
`StackTraceElement[]`	`getStackTrace()`	Provides programmatic access to the stack trace information printed by `Throwable.printStackTrace()`.
`final Throwable[]`	`getSuppressed()`	Returns an array containing all of the exceptions that were suppressed, typically by the `try`-with-resources statement, in order to deliver this exception.
`Throwable`	`initCause(Throwable cause)`	Initializes the cause of this throwable to the specified value.
`void`	`printStackTrace()`	Prints this throwable and its backtrace to the standard error stream.
`void`	`printStackTrace(PrintStream s)`	Prints this throwable and its backtrace to the specified print stream.
`void`	`printStackTrace(PrintWriter s)`	Prints this throwable and its backtrace to the specified print writer.
`void`	`setStackTrace(StackTraceElement[] stackTrace)`	Sets the stack trace elements that will be returned by `Throwable.getStackTrace()` and printed by `Throwable.printStackTrace()` and related methods.
`String`	`toString()`	Returns a short description of this throwable.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this object.
`final void`	`notify()`	Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()`	Wakes up all threads that are waiting on this object's monitor.
`final void`	`wait()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`final void`	`wait(long timeoutMillis)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis, int nanos)`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Constructor Details

MatchException

public MatchException(String message, Throwable cause)

Constructs an MatchException with the specified detail message and cause.

Parameters:: message - the detail message (which is saved for later retrieval by the Throwable.getMessage() method).; cause - the cause (which is saved for later retrieval by the Throwable.getCause() method). (A null value is permitted, and indicates that the cause is nonexistent or unknown.)

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